diff --git a/QtFrontend.cc b/QtFrontend.cc
index b2ea9a0..1963060 100644
--- a/QtFrontend.cc
+++ b/QtFrontend.cc
@@ -142,9 +142,11 @@ protected:
 				p.save();
 				p.setClipRect(viewport);
 
-				// Iterate visible lines
-				for (std::size_t i = rowoffs, vis_idx = 0; i < last_row; ++i, ++vis_idx) {
-					const auto &line   = static_cast<const std::string &>(lines[i]);
+    // Iterate visible lines
+    for (std::size_t i = rowoffs, vis_idx = 0; i < last_row; ++i, ++vis_idx) {
+        // Materialize the Buffer::Line into a std::string for
+        // regex/iterator usage and general string ops.
+        const std::string line = static_cast<std::string>(lines[i]);
 					const int y        = viewport.y() + static_cast<int>(vis_idx) * line_h;
 					const int baseline = y + fm.ascent();
 
diff --git a/default.nix b/default.nix
index b726470..8f6b1c6 100644
--- a/default.nix
+++ b/default.nix
@@ -6,8 +6,9 @@
   SDL2,
   libGL,
   xorg,
+  kdePackages,
+  qt6Packages ? kdePackages.qt6Packages,
   installShellFiles,
-
   graphical ? false,
   graphical-qt ? false,
   ...
@@ -37,12 +38,13 @@ stdenv.mkDerivation {
     xorg.libX11
   ]
   ++ lib.optionals graphical-qt [
-    qt5Full
-    qtcreator ## not sure if this is actually needed
+    kdePackages.qt6ct
+    qt6Packages.qtbase
+    qt6Packages.wrapQtAppsHook
   ];
 
   cmakeFlags = [
-    "-DBUILD_GUI=${if graphical or graphical-qt then "ON" else "OFF"}"
+    "-DBUILD_GUI=${if graphical then "ON" else "OFF"}"
     "-DKTE_USE_QT=${if graphical-qt then "ON" else "OFF"}"
     "-DCMAKE_BUILD_TYPE=Debug"
   ];
diff --git a/flake.nix b/flake.nix
index 902c01e..8d783ed 100644
--- a/flake.nix
+++ b/flake.nix
@@ -13,9 +13,9 @@
       packages = eachSystem (system: rec {
         default = kte;
         full = kge;
-        kte = (pkgsFor system).callPackage ./default.nix { graphical = false; };
-        kge = (pkgsFor system).callPackage ./default.nix { graphical = true; };
-        qt  = (pkgsFor system).callPackage ./default.nix { graphical-qt = true; };
+        kte = (pkgsFor system).callPackage ./default.nix { graphical = false; graphical-qt = false; };
+        kge = (pkgsFor system).callPackage ./default.nix { graphical = true;  graphical-qt = false; };
+        qt  = (pkgsFor system).callPackage ./default.nix { graphical = true;  graphical-qt = true;  };
       });
     };
 }